...The original 19th Century originals were WAY over sprung. Since those were the
sample examples copied, the Reproductions are also WAY over sprung....
Actually, this is not true. Originals were shipped with the spring screws NOT tightened all the way, to allow for adjustment. This is plainly stated in the original Winchester catalog. Uberti tightens the screw springs all the way which DOES result in the rifle being oversprung.
A lot of people have used this technique for the "poor man's action job":http://www.davidscottharper.com/shoot/PoorMan.htm
The appropriate Directions from Winchester are noted at the bottom of the article. Obviously you must do these adjustments within reason. Loosening screws too much will result in the carrier hanging up or the main spring not popping primers, same as if these springs had too much material removed during an action job. I have shot BP in .45, .357, and .44 Spcl straight wall cases with no action problems (and no slam down mod, either). The carrier may require a spritz during the match.